This is an invention devoted to data communications with applications to simple or complex multi-branched networks--usually of a private nature. Regardless of the transmission medium employed, two common problems are transmission noise and digital error. Accordingly, much time, expense, and engineering have gone into the solutions to these drawbacks.
One method of providing for increased reliability given a "quiet" transmission medium, has involved carrier ASK; at best this method has only produced results on the order of 3.times.10.sup.-2 errors per message.
Another method frequently used for achieving high speed reliable transmissions has been PLL constant carrier scheme whereby logical 1's and 0's are generated via PSK, FSK or FM techniques; however, the best coherent endeavors of this type typically yield results of around 9.times.10.sup.-4 errors per second on the most favorable kinds of transmission media.
It is therefore the object of this invention to devise a better, more error-free data encoding and transmission scheme for private data networks utilizing a variety of transmission media--particularly, noisy media. Low error rates are expected surpassing those above-quoted, and accordingly a variety of private data networks are herein disclosed, including modems which are capable of communicating or transporting data using a hybrid ASK/FSK scheme.